Traffic control system and apparatus



July 5, 1938. E. H. EAMES 2,122,411

TRAFFIC CONTRQL SYSTEM AND APPARATUS Filed larch 14, 1955 4 Sheets-Sheet 1 \75 Term. 52

7- 1/ Pefarud Qp-auf Pe/ay INVENTOR [on 400 H Bums 6mm, 801m A TTORNE Y5 July 5, 1938. E. H. EAMES 2,122,411

TRAFFIC GONTROL SYSTEM AND APPARATUS Filed llarch 14, 1935' 4 Sheets-Sheet 2 Side 5t g 9;; I? May 11v VENTOR [am/e0 H 5015.:-

mdd, 3.4; M

A TTORNE Y.

July 5, 1938. E. H. EAMES 2,122,411

TRAFFIC CONTROL SYSTEM AND APPARATUS Filed larch 14, 1935 4 Sheets-Sheet 3 raup onro era Group H Confmllcm 051v mAL f3 5 5734 now CO-OPD/NA T W6 UNIT 76 Term. 5/ 1 7rm. 32 3A k I26 i 25 Eg ATTORNEYS July 5, 1938.

E. H. EAMES TRAFFHLCONTROL SYSTEM AND APPARATUS Filed larch 14, 1935 4 Sheets-Sheet 4 /rad23' /ead2.9

ead$

' [(V VI? 1V TOR [pump hf [AM/5 A TTORNE Y Patented July 5,1938

UNITED STATES PATENT OFFICE .TRAFFIO CONTROL SYSTEM AND APPARATUS Application ll iarch 14, 1535, Serial No. 11,000

22 Claims.

This invention relates to trafilc control systems and has for its general object to provide a new and improved traillc controlling system and ap-. paratus therefor, capable of numerous different associations, but primarily designed for use at one or more of a plurality of intersections of a main trafllc lane with several cross lanes. Briefly, the invention comprises apparatus for connecting and disconnecting controllers at individual intersections to or from a coordinated system, de-

pending upon trafllc conditions existing from time to time.

The term "coordinated system or more generally the term coordination as used herein should be construed to mean any system of control of traflic signal timers or controllers at more than one intersection by which certain time relations are maintained between signal indications or signal changes at the several intersections.

' Systems have heretofore been proposed for transferring right of way at the intersection of a main traflic lane with a cross trafllc lane from the main to the cross lane at such times as trailic on the cross street may by appropriate means register its approach to the intersection. Other,

existing systems operate the control signals at a series of intersections, on a pre-arranged fixed time schedule regardless of immediate tramc densities or conditions, to accord right of way simultaneously to the main lane at all intersections for a predetermined period, and then to the side streets, or to transfer right of way to the side streets according to a pre-established progressive scheme.

Each of these systems above has certain disadvantages however. Individual trafllc-actuated control systems, when installed at a series of closely spaced intersections without interconnections or other inter-co-ordination, frequently cause traflic on the main highway to stop at successive signalized intersections in periods of moderate or heavy traillc. In periods of light trafllc, the fixed time co-ordinated systems impose unnecessary delay on traflic in the cross street during artery right of way. periods if meanwhile there is no trailic proceeding along the thoroughfare, and in periods of heavy trafllc vehicles on the artery awaiting right of way are needlessly delayed when there is no cross traffic, although the latter delay may be minimized with the progressive system. Another method of coordinating trailic actuated traflic control systems has also been proposed in which the response of local individual traflic-actuated signal controllers to traffic actuation is restricted to fixed periods determined by a master control. This restriction is of benefit to main highway traflic and does not excessively restrict cross traflic in moderately heavy orheavy trafiic, but it unduly penalizes cross traiilc in light traific conditions. 5

This invention provides means for bringing trafilc signal controllers at individual intersections in a seriesunder the control of a cosordinated system when traflic conditions make this desirable, and releasing them when conditions 10 make this desirable.

A primary object of this invention is to provide means for automatically releasing individual intersection controllers or groups of controllers from a master co-ordinating control when the 15 main highway is infrequently interrupted, and for automatically reconnecting the individual control or controls when the main highway is frequently interrupted.

Another object is to provide means associated 20 with an individual trafilc controller to connect it to or disconnect it from a co-ordination system in accordance with the frequency of interruption of right of way on the main trafllc lane'in the co-ordinated system. 25

A further object is to provide means associated with an individual controller to maintain it under control of a co-ordinated system for a predetermined number of cycles of the co-ordinated system after each interruption of right of way 30 4 on the main trafiic lane at the individual controller.

An additional object is to provide a traillc control system in which there is a means associated with each individual controller for maintaining it under control of the co-ordination system for a predetermined length of time following each transfer of right of way from the main to the cross lane at the intersection where said controller is located.

Another object is to provide apparatus of this character which will co-ordinate a series of traffic actuated signal controllers along a highway without any interconnecting wires except the A. C. power supply, in which is provided means 45 at an individual intersection controller to connect it to or release it from the co-ordination control in accordance with traffic actuation at the individual intersection.

Still another object is to provide apparatus employing a minimum of individually simple and well constructed parts such that the units upon assembling will comprise a system free from electrical and mechanical difliculties over long periods of time. 55

- this character which A still iurther object is to provide apparatus of will be adaptable with a minimum of changes to be used with many ditterent types oi traffic-actuated trafllc signal controllers. 7

Other objects will subsequently appear.

The invention will be described and its operatlon explained in detail in connection with the accompanying drawings, which illustrate practical-embodiments oi the'invention and in which:

Figure 1 represents schematically a series of intersections and apparatus embodying the invention associated therewith to control movement of trafllc through the intersections oi the cross trafllc lanes with the main trafilc lane.

Figure 2 is a wiring diagram for a traillc signal controller and signals, and one type of coordinating unit including rotary controller, regulating switch and associated apparatus for setting and maintaining traflic signals at one of the intersections. I

Figure 3 is a view or the lower regulating switch.

Figure 4 is a side view 01 the regulating switch.

Figure 5 is a view of the upper bank oi the same switch.

Figure 6 represents a second type or co-ordinator, in which co-ordination is retained for a definite period of time, instead of for a certain number of cycles, following transfer or right of way from the artery.

Figure 7 illustrates a modification oi the system in which the impulse generator for co-ordinating the individual controls is located at a central station.

bank of the Figures 8 and 9 are wiring diagrams for another form of simplified co-ordinating unit employing relays.

Figure 10 illustrates an alternative arrangement of the embodiment of the invention shown in Figure 2.

In Figure 1 of the drawings there is shown a complete, self-regulating system of traffic controllers installed at a series of intersections 0! a highway or principal trafiic'lane A, with several cross vehicle lanes, B, C, Y, Z, which intersect or end at the highway.

A control system at street B, for example, may be comprised of three parts; a vehicle detecting or responsive device N, placed in or at the side of the cross street vehicle lanes, a control mechanism D, composed of electrical timing and switching means, and a signal indicating device S, for indicating to trafflc when to go and when to stop. Similar equipment may be located at each of the protected intersections of the group.

The signals utilized in the present system may consist of a housing in which colored lamps, lenses, and/or reflectors may be employed to display, for instance, green, red, and yellow, indicating respectively the right of way, interruption of right of way, and an impending change in right of way in the main and cross streets, in accordance with familiar practice. Any of a number of well-known forms of signalling devices may be employed however in lieu of the type illustrated.

In the embodiments illustrated, pressure operated switches in the pavement units are operated by the weight of vehicles traversing them, but any other form of device which will control an operating circuit upon the approach of a vehicle to the intersection may be employed. The pedestrian push buttons are erected where they will be available for operation by persons desirous of crossing the main traific lane, and are connected in parallel with the vehicle detectors.

The control D may consist of two units; one, for timing the duration of the signal indications and eflectuating change of these indications, may be any of several well-known types of trafilc actuated controllers. Its operation may be govemed by the vehicle and/or pedestrian responsive devices. so that control of right of way is jointly regulated by the detecting means and the time control mechanism. The other unit iorming a part of the'control D is a coordination mechanlsm embodying the present invention and includes the apparatus for connecting and disconnecting the right oi way signal controller above to or from co-ordination control, depending upon trafllc conditions existing at the particular intersection.

Some features of the system in controllin traiilc are outlined as follows: first the operation of a type or local signal controller independent of co-ordination at one intersection will be described, and then the operation of the co-ordinating mechanism.

When operating independently, in the absence of trailic approaching the intersection on the side street, the local controller will indicate right of way to the highway A. A vehicle approaching on a side street, for instance street B, operates the actuating means N, and the controller, after causing a suitable warning to be displayed, transfers right of way from the highway to the cross street. ,Vehicles which operate the actuating means so near the end oi the side street right of way period that they have insufiiclent time to cross the intersection, affect the machine so that right of way will eventually be returned to the side street without additional actuation of the side street detector. Whenever right or way is accorded to the highway, it cannot be retransierred to the cross lane for at least a definite preestablished period, even if the side street detector should be actuated meanwhile.

Although operation of only one type of trafficactuated signal controller has been described here, co-ordlnating mechanism embodying the present invention can be utilized in conjunction with many other forms of trafllc actuated controllers including those provided with actuating means on the main highway, and those providing for variation of the side street right of way period by actuation as well as others.

Two alternative systems for connecting to and disconnecting from co-ordination a trailic actuated trafiic signal controller are disclosed herein. One type is shown diagrammatically in the lower portion of Figure 2. In this type, when, after a considerable period of absence of actuation, a vehicle actuates the detector in the associated side street and the'right of way is transferred to the side street, there is brought into operation a means to prevent the right of way transferring mechanism from again transferrring right of way to the side street after its return to the highway, except at definite intervals in the cycle of a background co-ordinatlng controller, viz. the synchronous motor-driven camshaft R and its associated cams and contacts. This means is efiective until a designated number of successive cycles of the background controller elapse following a transfer of right .0! way, in which cycles no traffic actuation is received. Controllers at the several intersections are similarly arranged, so that under conditions where more than one are operating in the ooordinatedm'anner,xightofwayistransferredto all these side streets, either simultaneously or in accordance with some progressive scheme,- for minimizing multiple ltopp l on the main high The second typ of functions similarly to the one whose opcration'was lust outlined, except that instead oi. maintaining the limiting influence of coordinated control for a certain number'of cycles following transfer of right-of way, co-ordination is retained fora definite length of time. A coordinationmechanism embodyins this principle is tieally represented in Figure 8, and its operation will rubsequently appear.

The details of construction of the coordination mechanism shown in the lower portion of Figure 2 will now be described and its use explained with the illustrative type of traffic actuated control mechanism shown in the upper portion of the same figure. Construction and operation of the latter will be described, but it will be appreciated that the present invention may readily be used, with or without certain changes in the. wiring, with many other types of right of way transferring mechanism besides the one shown. The embodiments of the invention herein will therefore be construed as illustrative alone.

In Figure 2, It and 4| indicate power supply leads from any suitable-source and'to. which.

for example, the lamps i 8--I8 may be connected in a manner hereinafter described. These lamps are contained within the signal 8, and similar sets are located within the similar signals at the other intersections controlled by the system.

A motor II. which may be electrically driven, drives shaft 2i, preferably through a reduction gear (not shown). A braflng device. III, which may be a magnetically operated friction brake, m y be employed to bring the motor quickly to a full stop and prevent revolution of the cam shaft Ii whenever the motor operating circuit isintenupted by relayl".- 0n theshaftll are mounted a number of spaced, adjustable cams, ILLJ.K.L,Meachinsulatedfrom the camshaft. Each cam may consist of two discs, each having a hub on one side, mounted with their faces together and their hubs outside, so that the sector of the effective portion of cm having major radius can be altered as desired by revolving one disc in respect to the other on the shaft. Each cam is held in its desired adjustment position and in its desired phase position on the shaft by set screws or other convenient means. Operating in coniunctionwith each of the cams are one or more circuit-making and breaking members, so arranged that whenever the portion of the cam having the larger radius is rotated into conjunction with the circuit-making member, the latter is pressed into engagement with its mate, enabling the circuit to be closed. Contacts KI and K2 which'can thus be closed by cam K are disposed in series with artery green and side street red illuminating units it and I6, between leads 5 and 46. Likewise,unlts i8 and I8, artery red and side street green, are in series with contacts K3 and K4, and yellow units It and 11 are energized through contacts J i and J2 and contacts II and II respectively.

The vehicle-actuated detector N and the pedestrian push button P in parallel with it are interposed between a relay E and ground. Also arranged-between relay E and grounded lead 45, paralleling the detector circuit. is a lead 23 in series with circuit breaker E3, 1314, which is a relay E, lead 28 and circuit breaker GI. G2,whieh, 'is a partoi'a third relay,relayG, whose function will be described hereinafter.

. When'relay l" is energized, its armature F2, en-

E is connected directly gageswith contact Pi and completes the circuit from leads 26, to the motor [hand when relay 1' is de energ'ized. the same armature F2 completes circuit through the braking m h nism 2. by engaging contact F1.

'rhepositionofthepartsshowninl'igureil is the'normal resting position thereof in any one of the machines of the group. The operation of such a machine, if allowed to function independ- 'ently. follows, starting in its resting position.

signal unitsil and It will be energized by a current flowing through lead 25, contacts K] and K2 and terminal and accordingly right of way willexistontheartery. 'lhecamshaitwillbein its rest position and stationary. If new a vehicle approaches along the side street at its intersection with the thoroughfare where the present controller is located, the vehicle will operate detector N, thereby momentarily energizing relay E. Belay Ewill continue to receive power, however, and remain lockedi n", by a circuicfrom lead 48, through lead 2|, cam contacts LI, L2, lead 28, contact E4 and armature E8.

The relay E will also attract its armature El,

which, assuming for the present the energization of the co-ordinstlng relay G and closure of its contacts. will close a circuit from lead 45, through lead II, contact E2, armature Ei,l'ead it to motor-controlling relay 1". This in turn pulls armature 1"2 away from contactFl. releases the brake mechanism 20, and by closing armature F2 against contact Fl. energizes the motor ll causing camshaft II torevolve slowly. As soon as camshaft II has rotated off the rest position. a circuit to relay 1' paralleling the one through circuit breaker El, E2, lead 16. just described, supplies power for the remainder of the cycle to relay F through lead 14, contacts El, E2. and lead 28, after relay E has become de-energized. Once the camshaft Ii has again reached the rest position, relay 1'' mustbe energized through lead 26 for restarting, since contacts Hi, H2, are open at this time.

. Upon the starting of camshaft Ii from rest the movement of. cams J and K will be such that by the closure of contacts Ji. and J2, yellow will appear on the artery in addition to the green, and shortly thereafter these lights will be replaced byartery red II and side street green it. since contacts KI and K4 will have come into engagement. Accordingly right of way will be transferred to the side street for a period of time determined by the shape and position of the cams andthespeedofthecamshaft.

At the termination of side street right of way interval, cam I causes yellow to appear on the side street by energizing unit ll through contacts II and I2. Artery green, II, and side street red, I, are restored a few seconds thereafter by camK whichcioses contacts KI and,K2. This condition of the signal 8 will be maintained throughout the remainder of the revolution of the camshaft to resting position, and thencefcrth until an actuation shall have been received either by detector N or by push button P, whereupon the cycle already described is repeated.

Provision is made for remembering the approach along the side street of a vehicle which cannot immediately be granted right of way, by means of the lock-in circuit. Actuation of the detector N energizes relay E and causes armature E8 to close circuit with contact E4. Current then flows through leads 48, 28, circuit breaker Li, L2, lead 22, contact E4, armature E8, relay E, to lead 28, and lead -48, and this continues to energize relay E until camshaft 2i has rotated to the side street green position. At this time cam L allows separation of contacts Li, L2, breaking the circuit.- Cam L may be, adjusted to lock-in detector relay E during side street red and amber periods, and also during the last few seconds of side street green period so that a vehicle approaching the intersection and failing to cross before right of way is shifted, insures that right of way will again be accorded to the side street at the earliest opportunity possible.

Before reviewing the operation 0'! a co-ordinating unit embodying the invention, an element of one type of unit, the regulating switch, will be reviewed.

Referring to Figures 3, 4, and 5, two discs 18, 80, of insulating material are rigidly fixed together, and two annular parts l1 and 18, also of suitable insulating material, are supported coaxially by the discs 19 and 88. Within the parts II and I8 are mounted two disc-shaped members 81 and 82. The members 8i and 82 are firmly mounted on the shatt 88. Pressure in the spring 84 caused by the nut 88 keeps members 8| and 82 firmly pressed against the plates 18 and 80 respectively. For rotating the plates 8| and 82 with respect to the insulating discs there is a manually operated knob 88 and a pointer 81 to indicate the amountot rotary displacement. A spring member 8! mounted on the underside of pointer 81 engages grooves 88 in the disc 81 for preventing the rotary portion of the switch from being set in a position where pointer .8! lies part way between integers on the dial.

A number or spring contacts 88 are mounted on the insulating disc 11 so that the free ends of the contacts bear on the rotatable member 8i A corresponding number of contacts 88 are mounted on disc 18 and their free ends bear on member 82. The fixed ends of all the contacts are adapted for connecting conductors thereto.

A commutator segment 88 of conducting material is securely mounted in'the disc 8|, in such a way that the upper surface of the segment is flush with the surface of the disc member." The are of the periphery of commutating segment 88, engageable with the contacts of bank 88. extends over 180 degrees. Another commutating segment 82 is similarly embodied in disc member 82, its width, however, is equal to the span of one of the spring contacts, and is positioned to engage contact #2-on bank 88, when segment 88 is engaging contact #1 on bank 88; contact #3 when segment 88 is engaging contacts #1 and #2, and so on, depending upon the position of indicator 81.

Also forming a part of this embodiment is a rotary controller or line switch, which is of a type well known to those familiar with the art. It is of the type frequently used in the dial switching systems of automatic telephony, and comprises a switch for selecting and connecting one circuit from a group of available circuits. It is operated by electrical impulsing. A switch of this charwwl acter is diagrammatically shown in connection with Figure 2. Energization and de-energization oi the line switch magnet T causes each oi! the three sets of wiper arms 12,18, 14 to be stepped ahead one contact on each of their respective contact banks.

I Reierringnow tothe lower part of Figure 2, one complete control mechanism i'or automatically placing the individual tramc actuated controller under co-ordinated control or releasing it from co-ordinated control in accordance with the invention will be described.

Wires '48 and 48 indicate power supply leads from an alternating current source, and from which by leads 4'! and 48 a synchronous motor 48 receives power. The motor 48 ope'ratescontinuously, and drives shalt 88, on which is mounted an adjustable cam R, insulated from the camshait. This cam is similar in ccnstructionand in its mounting on the shaft 88 to'the cams on shaft 2| described above. Likewise the circuit breaker RI, R2, can be of type similar to those disclosed above.

A circuit from lead 48 through lead 41, lead 88, cam-operated circuit breaker RI, R2, lead 88 to terminal 8i, and in turn by wire I, terminal 82 of the right of way controlling mechanism and co-ordinatlng relay G, which by leads 28, 48, is

rotary controller contains eleven contacts, and

each contact of bank 88 is connected to a corresponding contact in the upper bank of contacts 88 of the regulating switch. Connection is also made between each contact of bank 84 (except contact #11) and the corresponding contacts i-lli on the lower bank of the regulating switch. Wiper 12 on the top bank of the line switch is connected directly to the grounded power lead 45, and the wiper or commutating arm bearing on the upper banks of contacts 88 of the regulating switch is connected to lead 88 thus providing a second circuit to energize the relay G. In order for camshaft 2| of the right of way controller to leave its rest position, the relay G must be energized througheither one of these circuits and relay E must be locked-in, by detector actuation. The employment at other intersections of cams similar to cam R and driven by similar synchronous motors connected to the same power supply maintains a constant phase relation of the cyclic closure of cam contacts RI, R2 at the several intersections, and provides the basic means for co-ordinating the individual intersection right-of-way controllers.

Direct current for operating the magnet T of the line switch is supplied through leads 82, 83 from a rectifier 84 or other suitable controlled direct,current source. A filter condenser 85 is interposed between leads 82 and 83 for maintaining a near-constant voltage value.

The rectifier 84 operates from alternating current in leads 48, 48. Lead 88 electrically connects one input terminal of the rectifier 84 to lead 48. The other terminal is joined to lead 48, by lead 81, through wiper arm 14 of the stepping switch, contact bank 88, and lead 18 which is in series with contact U2, armature Ul of a relay U, and in series with contact T2, armature Ti which latter are operated by line switch magnet T.

In all contact positions of the wiper I4 except position #1, the circuit through wiper I4 is completed on bank 88 to contact U2, so that when relay U is energized, this circuit in lead III sup- .plies power to the rectifier 64, which in turn energizes line switch magnet T. Magnet T breaks the circuit to the rectifier between armature TI and contact T2, and magnet T is again de-energized. Each time the magnet T is energiz'ed and de-energized, the stepping mechanism of the line switch advances the wipers over their respective banks one contact. Hence when relay U is. energized (with the side street green signal as will be explained subsequently), wipers will automatically be advanced by the rapid stepping circuit of lead III from the position in which they were resting to the position where each wiper engages contact #1 on its associated bank.

A circuit through wiper I3 also may energize the line switch magnet T. when wiper Ii engages a contact on bank 84 which by the regulating switch is connected to commutating segment 90, the circuit from lead 51 to ground is completed over segment 90, lead 88, circuit breaker RI, R2, leads 89, 41, 45 to ground. Thus under this condition once during each cycle of camshaft ill when contacts RI, R2, are made and broken, magnet T is energized and de-energized, advancing the wipers one contact. The effect of this is to count revolutions of the cam shaft 50 which corresponds to counting cycles of the background coordinating controller.

One terminal of the relay U is connected to power lead It by lead I00, but the relay is energized only when the traillc signal at the intersection is indicating green to the side street, since the other terminal of relay U is connected to ground by lead I I, wire 2, lead 34, circuit breaker K4, K2, lead 25 and grounded lead 45. Contacts K2, K4 are closed only during the side street right of way period. The eflect of this is to reset the counting of cycles of the background coordinating controller each time the right of way is transferred to the side street.

The regulating switch provides a ready means to alter the number of cycles of camshaft 50 to be counted following last prior transfer of right of way from the highway and thus adjusts the number of such cycles during which co-ordinated operation of the signal is assured.after each transfer of right of way to the side street, and after which the right of way transferring mechanism is released from control by contacts RI--R2 of the coordinating controller. Asuming that it is desired to release the signal from co-ordination during the third successive cycle of the coordinating controller after the last preceding transfer of right of way from the highway, (which it will be noted is thethird successive actuation-less cycle or cycle without traillc actuation), the indicator 81 of the'regulating switch, which may be set at any number between one and ten inclusive, is accordingly placed on 3, so that commutating member 92 on the upper bank of the regulating switch will engage contact #3 of bank of contacts 89. In this position, commutating segment 90 will simultaneously engage contacts I and 2 of lower bank of contacts 88, and the other contacts on these banks of the regulating switch will remain disconnected.

Operation of this mechanism, in regulating the trafllc-actuated right of way transferring controller, at any particular intersection assuming for example the setting of the regulating switch indicator B1 to be set at three cycles, follows.

Assume, for example, for a starting position, that wiper arms 12, I8, 14 of the rotary line switch are'each engaging contact #3 on their respective banks. and that camshaft 2I of the controller is in its restins position. Camshaft ill will be revolving continuously at constant speed, the length of time required for each revolution is somewhat greater than that required by one revolution of camshaft 2i.

Current will flow from grounded lead 4!, wiper I2, contact #3 on bank 83 of the line switch, and contact #3 on upper bank 89 of the regulating switch, commutating arm 92, lead 89, wire I, through relay G, lead 28 to power lead 48. Consequently relay G will be energized, and will close armature GI against contact G2. Whenever these contacts are closed, the right of way transferring mechanism is in condition to start immediately from its rest position for transferring right of way in response to actuation of detector N which energizes relay E.

Therefore. if a vehicle now approaches along the side street B, for example, detector N will be operated whereupon relay E will be locked-in in exactly the same manner described in connection with the operation of the right of way transferring mechanism independently. A circuit from lead 46, through relay F, lead 28, armature EI contact E2, lead 28, armature GI, contact G2, to ground is thereby completed, energizing relay F and starting the motor.

When camshaft 2|- revolves to the side street green position where cam contacts K3, K4 are closed, relay U is energized by a circuit from power lead 48, through lead I00, relay U, lead 'II, wire 2, lead 34, circuit breaker K4, K3, lead 25, lead 45 to ground. During periods when relay U is energized, circuit is completed to operate rectiiler 84 through lead 61, wiper, I4, contact #3 on bank 95 of. the line switch, lead 10, circuit breakers UI, U2, and TI, T2, and grounded lead 45. Direct current thus is applied to leads 82, 81 energizing the line switch motor magnet T which breaks the circuit to the rectifier between armature TI, contact T2, andimmediately de-energizes the magnet '1' again. Energizing and deenergizing the magnet T causes the wipers I2, I8, I! to advance one contact on their respective banks. The relay U remains energized until the end of the side street green interval. Hence the circuit in lead III to the rectifier is again completed, through armature TI, contact T2, and now through contact #4 instead of #3, on the bank 95, and the stepping operation of the line switch is repeated until the wiper arms of the switch engage contact #1 where there is no further connection on bank 95, nor on any other bank, to again energize rectifier 64 under this condition.

Permissive co-ordinating relay G becomes disconnected from power when wiper I2 leaves contact #3. For this reason when camshaft 2I has revolved through the side'street green position and returned to its rest position where right of way is accorded to the artery it cannot again be revolved in response to detector actuation until relay G is energized.

During that part of each cycle of the constantly revolving cam shaft 50 when cam contact RI,

of way is so transferred to the said street, relay U is energized by the circuit fromleads 45, 25, through circuit breakers K3, K4 (which are closed during the artery red-side street green interval), wire 2, leads II, I00, 48, thus completing the line switch self-stepping circuit between contact U2 and armature UI, and the wipers are automatically stepped around to contact #1, in the manner described above, thus resetting the coordination release mechanism in preparation for recommencing the cyclic stepping of the wipers by contacts RI, R2 and resultant counting of actuationless cycles of shaft 60, i. e., the counting of cycles of the coordinating controller during which the artery green signal is displayed continuously by the right of way controller in the absence of trafilc actuation.

Thus if no trafflc actuation occurs the successive making and breaking of contacts RI--R2 in successive. cycles steps the line switch ahead successively one step per cycle until it reaches the point where it energizes relay G independently of contacts RIR2, which in the illustration described occurs in the third cycle. If for instance, no traflic actuation occurs in the first cycle but does occur in the second cycle, the right of way controller will transfer right of way tothe cross street as soon as the contacts RIR2 are closed in the second cycle and when the right of way is given to the cross street the stepping switch will very rapidly be self stepped back to position I. If traflic actuation is received only at the end of the third cycle or thereafter the right of way controller does not have .to wait for the next closing of contacts RIR2 but can transfer right of way immediately, and as before when right of way is given to the cross street the stepping switch is stepped rapidly back to its initial position.

While the co-ordinator regulating switch is set for release from co-ordination in the third actuation-less cycle following right of way transfer, and when the line switch wipers are engaging either contacts #1 or #2, the cyclic closure of contacts RI, R2 also completes the line switch notching circuitfrom leads 45, .41, 69, contactsv RI, R2, lead 68, segment 80, contacts on banks 88 and M, wiper 13, lead 61 to energize the rectifier 64. The energizing of the line switch magnet T and the consequent deenerglzing thereof, when cam contacts RI, R2 separate, advances the wipers one contact each time, in the aforedescribed manner.

When cam shaft 50 has completed two successive revolutions in which no detector actuations are received, the next closure of contacts RI, R2 completes the line switch magnet energizing circuit, and the wiper arms I2, I3, H are thereupon advanced to contact #3 on their respective banks.

When wiper 12 again engages contact #3 on bank 93, the circuit from power lead 46, lead 29, relay G, wire I, lead 99, contacting arm 92 of the regulating switch, contacts #3 on banks 89 and 93, wiper arm I2 to grounded lead 45, for energizing relay G is once more completed. In this position therefore, with irelay G energized, the right of way transferring mechanism is released from the limiting of the coordinating unit and upon actuation of detector N will forthwith accord right of way to the cross lane.

It is apparent that in lieu of setting the regulating switch indicator at I, it may be set at any integer between I and I0, whereupon in the cycle indicated following last previous transfer of right of way, the relay G will be energized, permitting independent response of the controller to actuation.

It will thus be observed that the release mechanism including the stepping switch in eifect counts successive cycles of cam shaft 50 of the coordinating controller during which there is no trafilc actuation, the mechanism being reset each time right of way is transferred to the cross street in response to actuation to count again when right of way returns to the highway. While the right of way is on the highway the counting continues only until a predetermined number of such successive actuation-less cycles-which may be preset on the regulating switch-have been counted whereupon the right of way controller is released from the restriction of the coordinatto lead 28, and that portion of lead 99 connectin with contact R2 is removed. Cam Q makes and breaks its contacts simultaneously with cam R.

Relay G and the alternative above described provide ways of eliminating possible feedbacks between the right of way controller and the stepping switch counting mechanism while right of way is being accorded to the side street and contacts RI, R2 are open.

In order that repeated transferring of right of way at a series of intersections will necessitate only a minimum of stopping of traffic proceeding along the artery, the cam shaft 50 in every machine is revolved at the same speed in a cycle of the same length. Thus each pair of contacts RI, R2, operated by cam R and mounted on each shaft 50, may be arranged to close in a definite phase relationship with the others. Either all pairs may be operated to close simultaneously or according to a predetermined scheme. Therefore, when the right of way controllers are operating under the control of the co-ordinating units, right of wayis transferred to all cross lanes having actuation in accordance with the pre-established scheme. After the required number of revolutions of camshaft 50 following last prior transfer of right of way, during periods when transfer of right of way to the cross lanes is infrequent, right of way transfer to a cross lane may be made independently of the co-ordination restriction immediately upon actuation.

As an alternative arrangement for the control mechanism shown in the lower part of Figure 2, a time relay may be substituted for the line switch and regulating switch in the co-ordinating unit disclosed. An embodiment utilizing this arrangement is diagrammatically shown in Figure 6. The relay 0, conveniently of the retarded dropout type, is connected to be energized through wire 2, leads I3I, I22, upon transfer of right of way from the artery. At the end of a predetermined period after the last prior transfer of right of way to the side street preferably a period equivalent to one or more cycles of the coordinating unit, the length of said period being determined by the setting of the time-delay relay 0, circuit is again completed by armature OI, and contact 02 to energize the local co-ordination mounted thereon.

' position,

relay G at terminal 32 which then permits the controller to respond promptly to further actuation. It will be obvious to those skilled in the art that in lieu of the exact arrangement shown in Figure 6, a retarded pickup time relay could be employed, to be energized during the highway right of way period, and close its contacts to energize local relay'G after a predetermined time.

The invention does not necessarily embody a synchronous motor driven camshaft with cams The impulses from grounded side of power supply for stepping ahead the line switch wipers and cyclically energizing co-ordination relay G, furnished in embodiment of Fi ure 2 from leads 45, 41 by cam R when its contacts RI, R2 are made to engage, may be supplied from any convenienttype of impulse generator which may be located, for example as in Figure '1', at a central station and transmitted to each individual co-ordinating mechanism.

In Figures 8 and 9 are shown further alternative, simplified forms of the co-ordinating unit, which may be substituted for the unit compris ing the lower part of Figure 2. The types shown in Figures 8 and 9 will respectively retain the right of way controllers with which they operate under co-ordination for-one and two revolutions of the camshaft 50 following the last prior trans fer of right of way to the cross lane. This arrangement utilizes cams and relays, and the line switch and regulating switch are eliminated.

Referring again to the upper unit ofFigure 2, there is mounted on camshaft 2| a cam M, arranged to close the pair of contacts Ml, M2 when camshaft 2| is in the rest' position. Contact M| is connected to leads 28, 46: contact M2 to terminal 3L. Now-referring to Figure 8, relay V is connected between'terminal 3| and'contact R2 by wire 1, leads I25, I26. A circuit from lead 41 passes through contacts VI. V2, then through lead 8, wire I to contact 82 and co-ordinating relay G of the right of way controller: a second circuit from lead 41 is a lock-in circuit for relay V, and includes contacts V3, V4, and lead |2| to lead |26.

Assume that the camshaft 2| is in its rest during which right of way is displayed to the highway. Synchronous motor 49 constantly rotates shaft 50 and periodically contacts RI R2 make contact with each other, thus energizing relay V through leads |26, I25, wire 3, contacts M2, Ml, leads 29, 46. Relay V remains energized by the lock-in circuit from lead 41 across armature V3. contact V4. Another armature of relay V, VI, energizes contact V2 and completes circuit to the co-ordination relay G, whereupon camshaft 2| may be revolved in response to detector actuation. By leaving the rest position, camshaft 2| interrupts the energizing circuit to relay V between contacts Mi, M2, and thus further response to actuation by the controller is not possible until shaft 2| has again reached its rest position and co-ordinating contacts RI and R2 engage.

Similar arrangements in which the line and regulating switches are dispensed with may be set up for retaining coordination for any desired number of cycles of the camshaft 50 following last previous right of way transfer to the side street. Figure 9 shows such a system whereby coordination is'retained over two cycles. When the apparatus of Figure 9 is used in conjunction with the traflic actuated signal controller forming the upper part of Figure 2, contact Mi of the controller is connected to leads 25 and. 45 to minus, instead of to leads 2S and 46 to plus as shown.

Cam .Q makes and breaks its contacts Ql, Q2, and Q3, Q4 just before the cam R closes contacts RI, R2. During the first cycle of shaft 50' after shaft 2| has returned to rest position the contacts RI R2 close, energizing and locking-in relay X, and in the next cycle circuit to energize relay W is completed through contacts Qi, Q2 and armature Xi, contact X2. The function of .relay W, similar, to that of relay V in Figure 8, is to energize permissive co-ordinating relay G.- The closing of contacts Q3, Q4'during each cycle periodically enelglzes the relay G through lead I30, to permit response of the controller to actuation once per revolution of shaft 50. It is desirable that the time cycle of shaft 2| be somewhat less than the time cycle of shaft 50.

Summarizing, it will be'seen from the foregoing that the structures illustrated in the lower part of Fig. 2, and in Figs. 6, 'l, 8 and 9 are alternative coordination and coordinating release arrangements for use with a right of way transferring mechanism of the'type shown in the upper portion of Fig. 2 or with other well-known corresponding types of such mechanism, and that all of these alternative coordination mechanisms have a common purpose. Thus, in periods when transfer of right of way from the main highway at an intersection is made frequently, the right of way transferring mechanism thereat is connected to' and retained under the control of the coordinating controllerunit in order thatsuch transfers will be made in predetermined relation with the coordinated system at times determined by the coordinating controller. When the time frequency of interruptions to the main highway traflic decreases sufliciently the local right of way transferrring mechanism is released from the coordinating controller so" that right of way can be transferred to the side street immediately in response to traific actuation and consequently delays to cross street trafllc will be minimized. As -pointed out above the frequency of interruption is measured under certain alternative arrangements by counting up to a certain point the number'of cycles of the coordinating controller during which no transfer of right of way from the highway has occurred by the right of way control and under other alternative arrangements thisfrequency is determined by measuring up to a certain point the time after any transfer of right of way from the highway and during which no transfer of right of way occurs. In either case when the certain point is reached the right of way controller is automatically released from the coordinating controller until the next transfer of right of way from the highway when the right of way controller is again placed under the control of the coordinating controller.

From the foregoing it will be appreciated that embodiments of the present invention obtain the advantages of coordinated traific control for a series of intersections in heavy trafllc conditions, without imposing unnecessary delay to cross lane traffic in light traffic periods, since in the latter periods for a large part of the time right of way can be allowed them promptly upon actuation of the detectors, independent of any co-ordination control if the main highway has had a considerable period of right of way free from interruption. Thus the specific objects enumerated and others are achieved. It is understood that various modifications may be made in the design and structural details herein exemplified, without deas new and desire to secure by Letters Patent of the United States is as follows:

i. In a tramc signal control apparatus for the intersection of a cross lane with a main traiiic 1 lane having a trailic actuatable means in. the

cross laneand a right of way transferring controller connected to said traiilc actuatable means for normally according right of way to the main traflic lane and operable thru a cycle to transfer right of way to the cross lane and retransfer right of way to the main lane, means forming a part of the controller for initiating cyclic operation of the controller in response to actuation of said actuatable means, a master control means for periodically determining when cyclic operation of the controller may be initiated in response to actuation, and a means for releasing the cyclic operation initiating means from such determining effect by the master control means a predetermined period after thelast transfer of right of way from the main lane.

2. In a trafllc signal control apparatus for the intersection of a cross lane with a main tramc lane having a traillc actuatable means in the cross lane and a right of way transferring controller connected to said traflic actuatable means for normally according right-of way to themain traiilc lane and operable thru a cyeleto transfer right of way to the cross lane-and retransfer right of way to the main lane, means forming a part of the controller for initiating cyclic operation of the controller in-response to actuation of said actuatable means. a cylic master control means operating in cycles for periodically determining when cyclic operation of the controller may be initiated in response to actuation, and a means operable a predetermined number, of such cycles of the master control means after the last transfer of right or way' from the main lane for releasing the cyclic operation initiating means from such determining effect by the master control means.

3. In a trafllc signal control system for an intersection of a cross road with a main highway having a right of way according and transferring mechanism and a master control connected to the right of way controlling mechanism and cyclically operable to determine the time when transfor of right of way by said mechanism to the crossroad may occur, trafllc actuated means associated with said cross road, means associated with the right of way transferring mechanism to cause right of way to be accorded normally to the main highway and solely upon actuation of said traffic actuated means to cause transfer of right of way to its cross road at the time determined by said master control and thereafter retransfer right of way to the main highway, and means operable a predetermined time after said retransfer to release said mechanism from such determining effect by said control and so afi'ect said mechanism that it will transfer right of .way immediately upon actuation at any time independently of such determining sheet of said master control.

4. In a trafilc control system for the intersection of a cross road with a main highway the main highway and adapted upon actuation of said traiiic actuatable means to transfer right of way to the crossroad and then retransfer it to the highway. a master control timerv con-. nected to said right of way transferring mechanism and operable" cyclically to control said mechanism in a part of its cycle preventing said mechanism from operating in response to actuation of said trafllc actuatable means and in a second part of its cycle causing response to actuation occurring in either part of such cycle, means connected to said master timer and-said l0 mechanism and operable after a predetermined" interval of time longer than the timer cycle and in which right of way remains continuously on the highway to render said mechanism immediately responsive to the first actuation occurring l5 thereafter in any part of the timer cycle.

5. In a traffic signal control apparatus for the intersection of a cross lane with a main traiflc lane having a traffic actuatable means in-the cross lane and a right of way transferring controller connected to said trafllc actuatable means for normally according right of way to the main trafiic lane and operable thrua cycle to transfer right of way to the cross lane .and retransfer right of wayto the main lane, means forming a part of the controller for initiating cyclic operation of the controller in response to actuation of said actuatahle meanaa master control means for periodically determining when cyclic opera tion of the controller may be initiated in response to actuation, and a time controlled switch means operating at the end of a predetermined time period of continuous right of way on the main lane longer than the period of such periodic operation of the master control to release the cyclic operation initiating means from such determining eflect by the master control means to permit the initiating means to function immediately upon actuation independently of such determining eflect until the next transfer of right of way to the main lane.

6. In a trafllc signal control system for the intersection of a cross road with a main highway having a right of way transferring mechanism at the intersection and traific actuatable means inthe cross road, said mechanism normally according right of way to the main highway and adapted upon actuation of said trafllc actuatable means to transfer right of way to the cross road and then retransfer it to the highway, a master control connected to said right of way transferring mechanism and effective immediately after any such retransfer to the highway to provide a cyclically repeated time cycle of control therefor in a part of which cycle said mechanism is prevented from so transferring right of way from themain highway upon actuation and in the other part of which cycle said mechanism is permitted to so transfer right of way immediately upon actuation, and means as sociated with said mechanism and operable after a predetermined interval of right of way on the highway longer than one such time cycle to render said master control inefiective over said mechanism and to permit said mechanism to so transfer right of way immediately in response to actuation occurring in any part of the master time cycle independent of said master control.

'7. In a traiilc signal control system for the intersection of a cross road with a main highway having a right of way. transferring mechanism at the intersection and trafllc actuatable means in the cross road, said mechanism normally according right of way to the main highway and adapted upon actuation of said trailic actuatable means 75 to transfer right of way to the cross road and then retransfer it to the highway,'a master control connected to said right of way transferring mechanism and to provide. when effective a cyclically repeated time cycle of control therefor in a part of which cycle said mechanism is prevented from so transferring right of way from the main highway upon actuation and in the other part of which cycle said mechanism is permitted to so transfer right of way immediately upon actuation, and means associated with said mechanism and operable after a predetermined interval of right of way on the highway longer than one such time cycle after transfer of right of way to the cross road to render said master control ineffective over said mechanism and to permit said mechanism to so transfer right of way immediately in response to actuation occurring in any part of the master time cycle independent of said master control, means operated by said mechanism upon any such transfer and retransfer of right of way to render aid master control so effective immediately after such retransfer to the highway.

8. A tramc signal control apparatus for the intersection of a main trafiic lane with a cross lane having trafiic actuatable means in the cross lane, a right of way transferring controller for according right of way normally to the main lane and upon actuation of said traffic actuatable means transferring right of way to the cross lane and retransferring it to'the main lane again, master control means connected to said controller to provide a cyclically repeated time cycle in a part of which cycle transfer of right of way is permitted immediately in response to actuation. and in the remaining part of the cycle transfer of right of way is postponed until the end of such remaining part of the cycle, and means operable after a predetermined period longer than one such time cycle has elapsed during which right of way has remained continuously on the main lane to render said master control means ineffective until after the next sotuation occurring at any time thereafter as lon as right of way remains on said main lane, whereby right of way is transferred immediately in response to such actuation.

9. A traffic signal control system for the intersection of a crom trafllc lane with a main lane having, in combination, a traffic actuatable device in the cross lane, a tramc signal controller connected to the tramc actuatable device for controlling a traflic signal to accord right of way normally to the main lane and upon actuation of the said actuatable device to transfer right of way to the cross lane, a master control unit connected to said controller and including a cyclic mechanism operable through a cycle and having means effective upon transfer of right of way from the main lane by said controller for restricting said controller from again transferring right of way from the main lane except at a predetermined point in the cycle of said cyclic mechanism in response to actuation occurring at or prior to said point, and further means operable after a predetermined number of cycles when and during which there has been no transfer of right of way from the main lane to release said controller from the restricting effect of said restricting means and to permit immediate transfor in response to the next actuation at any time.

10. In 'a trafiic signal control system for the intersection of a cross road with a main highway having a right of way transferring mechanism at the intersection and traillc actuatable means in the cross road, said mechanism normally according right of way to the main highway and adapted upon actuation of said traiilc actuable means to transfer right of way to the cross road and then retransfer it to the highway, a master control'connected to said right of way transferring mechanism and effective immediately after any such retransfer to the highway to provide a cyclically repeated time cycle of control therefor in a part of which cycle said mechanism is prevented from so transferring right of way from the main highway upon actuation and in the other part of which cycle said mechanism is permitted to so transfer right of way immediately upon actuation. and means associated with said mechanism and operable after a predetermined number of such cycles of the master control occurring while right of way is continuously accorded to the main highway to render said master control ineffective over said mechanism and to permit said mechanism to so transfer right of way immediately in response to actua tionoccurringinanypartofthemastertime cycle independent of said master control.

11. In a tramc signal control system for the intersectionof a main lane with a cross traiilc lane. the combination of a traiiic actuated device in the cross lane. a traffic signal controller connected to said actuatablc device for according right of way normally to the mainlane and in response to actuation of the actuate-hie device transferring it to the cross lane and after a pre-,

determined period retransferring right of way to the main lane, and a master control unit associated with the right of way controller operable through a cyclically repeated cycle to govern op eration of said controller, each such cycle of said master control iinit having a first and second to part, means including a circuit closed only in the second part of such cycle for permitting said eontroiler to transfer right of way to the cross lane in response to actuation of said tramc actuatable means occurring in the first or second part of the control unit cycle and means for opening said circuit in the first part of the cycle for preventing said controller from transferring right of way during said first part of the cycle. and further means operable after a predetermined number of cycles of the master control unit have elapsed during which there has been no transfer of right of way from the main lane to render said right of way controller immediately responsive to the first actuation occurring thereafter in any part of the time cycle.

12. A trafilc signal control apparatus for the intersection of a cross traific lane with a main lane having a tramc actuatable device in the cross lane and a right of way transferring controller connected to said tramc actuatable device.andnormally resting to accord right of way to the main lane and operable when started to transfer right of way to the cross lane for a predetermined period and then to retransfer right of way to the main lane and return to rest, a master timer connected to said controller and comprising a circuit when closed for starting said. controller, a'

cam operated circuit closer closed periodically for predetermined intervals alternated with opening thereof for predetermined intervals for preparing said circuit only during intervals of closure,

means operable upon actuation of the tramc actuatable device in the cross lane to complete said circuit when prepared for starting said controller,

means for counting successive periodicclosings of said circuit closer in preparing said starting circuit when and during which there is no right of way transfer from the main lane, means operable after a predetermined number of said closings to continuously prepare said starting circuit for immediate completion thereof by said circuit completing 'means operable upon actuation of said actuatable device, and means operable upon 'the next transfer of right of way from the main lane to render said last named means inoperative again until a further predetermined number 0 said closings has again been counted. 13. A trafllc signal control system for the intersection of a cross lane with a main trafllc lane having, in combination, a traffic actuatable device in the cross lane, a traffic signal controller connected to said actuatable device for according right of way normally to the main lane and when permitted, transferring right of way to the cross lane for a predetermined period in response to actuation of said cross lane actuatable device, and, connected to the controller, means including a circuit and operable only when the circuit is closed for permitting the controller to transfer right of way to the cross lane in response 'to actuation of said actuatable device, means for closing and reopening said circuit periodically to restrict the time of transfer of right of way from the main lane to such periodic closings of said circuit, a rotary step-by-step switching mechanism having a starting position and a series of other positions through which it is stepped periodically by such periodic closings of said circuit. means operated by the step-by-step switching mechanism after a predetermined number of successive closures of said circuit forpermitting the controller to transfer right of way to the cross lane at any time in response to actuation of the actuatable device, and means operable upon the next transfer of right of way from the main lane to reset said step-by-step switching mechanism to its starting position to render said'last means ineffective so as to again restrict transfer by the controller in response to actuation of said actuatable device to such periodic closings of said circuit. 4

14. A trafilc signal control apparatus for the intersection of a cross lane with a main traflic lane including a traffic actuatable device in the cross lane, a right of way transferring control connected to said trafllc actuatable device and normally according right of way to the main lane and in response to actuation of the said actuatable device operable through a cycle in which right of way is accorded to the cross lane and then retransferred to the main lane, means for storing the effect of actuation while right of way is on the main lane until right of way is transferred to the cross lane in response thereto, a periodic timer associated with the controller and operable upon transfer of right of way to the cross lane to time a time period longer than the right of way cycle of said controller, means operable upon transfer of right of way from the main laneto prevent further transfer of right of m from the main lane except at the completion of the time period by the associated timer whereupon such transferls permitted in response ,to actuation occurring in the time period, and

further means operable upon completion of a predetermined number of timing 'periods when and during which there has been no transfer of right of way to release the right of way trans- !erring controller from the restricting effect of according right of way to the main lane and upon actuation of said tramc actuatable means transferring right of way to the cross lane and after a predetermined period retransferring right of way to the main lane, means for storing the effect of actuation of said actuatable means when right of way is on the main lane until right of way is transferred in response to such actuation, and a cyclic master timer operating in cycles for determining fixed periods in such cycles only during which periods can the right of way transferring'mechanism respond to actuation of the actuatable device during such cycle, an apparatus comprising means operable upon transfer of right of way from the main lane for automatically connecting-said right of way transferring mechanism to said cyclic master timer, means for counting successive cycles of saidtimer when and in which there is no transfer of right of way from the main lane andoperable upon completion of a predetermined number of cycles automatically to release said right of way transferring mechanism from such determining effect by such master control timer.

16. In a tramc signal control system for the intersection of a cross traflic lane with a main lane having a trafiic' actuatable means in the cross lane, a right of way transferring mechanism connected to said trafllc actuatabie means normally according right of way to the main lane and upon actuation of said trafllc actuatabie -means transferring right of way to the cross lane and after a predetermined period retransferring right of way to the main lane, means for storing the effect of actuation of said actuatable means when right of way is on the main lane until right of way is transferred in response thereto, and a cyclic master control timer operating in cycles for determining fixed periods in such cycles only during which periods can the rightof way transferring mechanism respond to actuation of its tramc actuatable device. an apparatus comprising means operable upon transfer of right of way from the main' lane for automatically connecting said right of way transferring mechanism to said cyclic master control timer, means operable after a predetermined number of cycles of the said cyclic timer in which there has been no transfer of right of way from the main lane automatically to release said right of way transferring mech-- anism from such determining effect by said master control timer, and adjusting means including a manually operated switch for altering said predetermined number of cycles of the cyclic master control timer before the right of way transferring mechanism is automatically released.

1'7. A traillc signal control system for the intersectidn of a cross traificlane with a main lane and having trafllc. actuatable means in the cross lane, a right of way transferring mechanism normally testing to accord right of way to the main lane and upon actuation of the actuatable means operable through a cycle in which right of way is transferred to the cross lane and thereafter retransferred to the main lane, means for storing the eilect of actuation of said actuatable.

means when right of way is on the main lane until right of way is transferred in response thereto; cyclic master control means operating in cycles and associated with the right of way transferring mechanism for limiting transferring of right of way from the .main lane to once per cycle of said master control means, means ineluding a rotary stepping switch for counting successive cycles of said master control means when and during which there is no.transfer'of right of way from the main lane, means operable after a predetermined number of said successive cycles for releasing said right of way transferring mechanism from suchllimiting effect of the master control means for allowing immediate transfer of right of way in responseto actuation, means operable upon the next transfer of right of way from the main lane to'reconnect the-master control means to said transferring mechanism to reestablish such limiting effect, and adJusting means comprising a manually operated switch for altering said predetermined number of cycles of. said master control means.

18. A traffic signal control system for a series of intersections of cross lanes with a common main trafiic lane having at each intersection. in combination. a traillc actuatable device in the cross lane. a traiilc signal controller connected to the actuatable device in thecross lane thereat for according right of way normally to the main lane and when permitted. transferring right of way to the cross lane for a predetermined period in response to actuation of said cross lane actuatable device, and, connected to the controller, means including a circuit and operableonlywhenthecircuitisclosedforper-' mitting the controller to transfer right of way tothecrosslaneinresponsetoactuation of the said actuatable device, means for closing and resaid circuit periodically and in a'predetermined' relationship with the closure of corresponding circuits at other controllers to restrict the time-of transfer of right of way from the main lane to such periodic clodngs of said circuit. means including a rotary step by step switching mechanism effective after a predetermined number of successive clmures of said circuit for permitting the controller to transfer rightofwaytothecrosslaneatanytimeinresponse to actuation of the actuatable device, and means operable upon the next transfer of right of way from the main lane to render said last named means ineffective so as to again restrict transfer by the controller in response to actuation of said actuatable device to such periodic closings of said circuit.

19. In a traffic signal control system for one of a plurality of intersections of a main lane with cross trafllc lanes, the combination of a traiilc actuatable device in the cross lane, a tramc signal controller connected to said actuatable device for according right of way normally to the main lane and in response to actuation of the aetuatable device transferring it to the cross lane and after a predetermined period retransferrlng it to the main lane, and a master control unit associated with the right of way controller operable cyclically in. time cycles to govern operation of 'said controller. each cycle of said master control unit having a first and second part, means including a circuit closed only in the second part of such cycle for permitting said controller to transferright of way to the cross lane in response'to actuation of said trailic actuatable meansoocurringintheilrstorsecondpartofthe control unit cycle and means for opening ai circuit in the first part of the cycle for preventing said controller from transferring right of way during said first part of the cycle. a synchronous motor for driving said master control means for opening and closing said circuit cyclically in step with corresponding units at other intersectlons, and further means operable after a pre determined number of cycles of the master control unit have elapsed during which there has been no transfer of right of way from the main lane to render said right of way controller immediately responsive to the first actuation oc curring thereafter in any part of succeeding of. said time cycles.

-20. In a traffic signal control system' for a plurality of intersections of cross traffic lanes with a common main'lane having at each intersection a traffic actuatable means in the cross lane, a right of way controller normally according right of way'to the main lane and upon actuation of the said actuatable device in the cross lane transferring right of way to the cross lane and retransferring it to the main lane, and

a cyclically operating master timer connected to said controller for restricting said controller to so transfer right of way only in predetermined relation with the controllers at other intersections 5 when effective, and means responsive to the time spacing of transfer of right of way from the main lane in response to actuations at any one such controller for rendering said master timer effective as to such one controller when the time spacing of transfer of right of way from the main lane by such one controller is less than a predetermined value and 'for rendering said master timer ineffective as to such one controller when the time spacing of transfer of right of way from the main lane by such one controller in response to actuations is greater than said predetermined value whereby said one such controller may transfer rightof way immediately in response to traiiic actuation when said master timer is ineffective.

21. A traillc control system for the intersection of a cross lane and a main traiilc lane hav ing a turtle actuatable means in the cross lane, a right of way transferring mechanism connected to said actuatable device and normally according right of way to the main lane and operable upon actuation of said actuatable device to transfer right of way to the cross lane and thereafter retransfer right of way to the main lane, master control means connected to said right of way transferring mechanism and operating continuously and cyclically to determine when eifective periodic times for such transfer of right of way in response to such actuation and including means operable when the frequency of actuations causing such transfer is less than a certain frequency to render said master control in effective so a s to permit immediate transfer of rightofwaybysaldmechanisminresponseto said actuations at any time. and means operable upon the frequency of actuations causing such transfer increasing to said certain frequency and remaining substantially at said certain frequency to render said master control means eifective so as to limit to said certain frequency as a maximum the frequency of further transfer of right of way from the main lane in response to such actuations.

22. A traillc control system for the intersection of a cross lane and a main traiiic lane having a mum actuatable means in the cross lane,

nected to said actuatable device and normally according right of way to the main lane and operable upon actuation of said actuatable deaiaalii means ineflectiye so as to permit immediate transferof right of way by said mechanism in response to said. actuations at any time. and means operable upon the frequency of actuations l vice to transfer right of way to the cross lane causing such transfer increasing above said cer- 5 and thereafter retransfer rightof way to the tain frequency and remaining'above'said fremain. lane, master controlmeans connected to quency to render said master control effective so said right of way transferring mechanism to conas to limit between said certain frequency and a trol when elective the time of transfer of right predetermined greaterfrequency as a maximum 1Q ofway in response to such actuation and inclu'd'-- the frequency of further transfer of right of way 10 tain frequency, to render said master control in: means operable when the frequency of actuations causing such transfer is less than a cercanrrrrcara or It is hereby certified that error appears from the main lane in response to such actuations.

CORRECTION.

-'.Tu1y 5, 1958.

in the printed specification of th'e'above numbered patent requiring correction as follows: Page 12, first column, 111; 8 m9, claim '22,- fox-the worda -ltoeontrol-vmen effective thetime of! read "anioperatingcontinuousiy and cyclically to determine nkhen effect iye per'iodic til nee .f'or Ieueh; and that the said Letters Patent be read with: this-correction therein that the e .;-e ora of the case in .thefatent m some mayconform to;

' signed and sealed can let an or au ust; L .'1 939.I

Emmi

hoary vanfirsdale, Acting commissioner of Patents.

nected to said actuatable device and normally according right of way to the main lane and operable upon actuation of said actuatable deaiaalii means ineflectiye so as to permit immediate transferof right of way by said mechanism in response to said. actuations at any time. and means operable upon the frequency of actuations l vice to transfer right of way to the cross lane causing such transfer increasing above said cer- 5 and thereafter retransfer rightof way to the tain frequency and remaining'above'said fremain. lane, master controlmeans connected to quency to render said master control effective so said right of way transferring mechanism to conas to limit between said certain frequency and a trol when elective the time of transfer of right predetermined greaterfrequency as a maximum 1Q ofway in response to such actuation and inclu'd'-- the frequency of further transfer of right of way 10 tain frequency, to render said master control in: means operable when the frequency of actuations causing such transfer is less than a cercanrrrrcara or It is hereby certified that error appears from the main lane in response to such actuations.

CORRECTION.

-'.Tu1y 5, 1958.

in the printed specification of th'e'above numbered patent requiring correction as follows: Page 12, first column, 111; 8 m9, claim '22,- fox-the worda -ltoeontrol-vmen effective thetime of! read "anioperatingcontinuousiy and cyclically to determine nkhen effect iye per'iodic til nee .f'or Ieueh; and that the said Letters Patent be read with: this-correction therein that the e .;-e ora of the case in .thefatent m some mayconform to;

' signed and sealed can let an or au ust; L .'1 939.I

Emmi

hoary vanfirsdale, Acting commissioner of Patents. 

